As a conventional system in which video and audio data is transmitted among a plurality of node devices, there has been a system using HDMI (High-Definition Multimedia Interface) defined in Non-Patent Document 1. In an HDMI system, a transmitter node device transmitting video and audio data (e.g., a video and audio player such as a DVD player) reads, via a DDC (Display Data Channel), EDID (Extended Display Identification Data) of a receiver node device (e.g., a TV, etc.) connected thereto through an HDMI cable, and thus obtains necessary format information. The format information includes a video format and an audio format that are supported by the receiver node device. Based on the obtained format information, the transmitter node device determines the format of data to be transmitted. Determined video format information is transmitted to the receiver node device with the information being multiplexed with video data.
When a user presses a playback button of the transmitter node device, the transmitter node device transmits an Active Source message to the receiver node device so that the receiver node device switches its input, and thus, the receiver node device can immediately display a video played back by the transmitter node device.
Further, Patent Document 1 discloses an AV system including a display device, a plurality of video devices connected to the display device, and remote controls corresponding to the video devices and for controlling them; and capable of operating the video devices by using the remote controls in direction of the display. When a button of each remote control is pressed, the remote control transmits to the display device a remote control code including at least one of a manufacturer code and device code corresponding to each video device. Based on the remote control code transmitted from one remote control, the display device connects to the display device one of the video devices corresponding to the remote control, thus switching its input.
Patent Document 1: Japanese Patent laid-open Publication No. 2004-208290, and
Non-Patent Document 1: High-Definition Multimedia Interface Specification, Version 1.1, HDMI Licensing, LLC, California in U.S.A., May 20, 2004.